Technologies for latency based service level agreement management in remote direct memory access networks

ABSTRACT

Technologies for latency based service level agreement (SLA) management in remote direct memory access (RDMA) networks include multiple compute devices in communication via a network switch. A compute device determines a service level objective (SLO) indicative of a guaranteed maximum latency for a percentage of RDMA requests of an RDMA session. The compute device receives latency data indicative of latency of an RDMA request from a host device. The compute device determines a priority associated with the RDMA request as a function of the SLO and the latency data. The compute device schedules the RDMA request based on the priority. The network switch may allocate queue resources to the RDMA request based on the priority, reclaim the queue resources after the RDMA request is scheduled, and then return the queue resources to a free pool. Other embodiments are described and claimed.

BACKGROUND

Data centers and other distributed computing systems may include disaggregated I/O components, such as pooled storage devices. Remote direct memory access (RDMA) networks may be the basis for distributed I/O. Some RDMA networks may require lossless quality of service (QoS), which may be difficult to manage. In typical networks, device ports that service RDMA may use QoS mechanisms such as IEEE priority flow control (PFC) or data center bridging (DCB), which may slow down performance and lead to head of line blocking.

BRIEF DESCRIPTION OF THE DRAWINGS

The concepts described herein are illustrated by way of example and not by way of limitation in the accompanying figures. For simplicity and clarity of illustration, elements illustrated in the figures are not necessarily drawn to scale. Where considered appropriate, reference labels have been repeated among the figures to indicate corresponding or analogous elements.

FIG. 1 is a simplified diagram of at least one embodiment of a data center for executing workloads with disaggregated resources;

FIG. 2 is a simplified diagram of at least one embodiment of a pod that may be included in the data center of FIG. 1;

FIG. 3 is a perspective view of at least one embodiment of a rack that may be included in the pod of FIG. 2;

FIG. 4 is a side elevation view of the rack of FIG. 3;

FIG. 5 is a perspective view of the rack of FIG. 3 having a sled mounted therein;

FIG. 6 is a is a simplified block diagram of at least one embodiment of a top side of the sled of FIG. 5;

FIG. 7 is a simplified block diagram of at least one embodiment of a bottom side of the sled of FIG. 6;

FIG. 8 is a simplified block diagram of at least one embodiment of a compute sled usable in the data center of FIG. 1;

FIG. 9 is a top perspective view of at least one embodiment of the compute sled of FIG. 8;

FIG. 10 is a simplified block diagram of at least one embodiment of an accelerator sled usable in the data center of FIG. 1;

FIG. 11 is a top perspective view of at least one embodiment of the accelerator sled of FIG. 10;

FIG. 12 is a simplified block diagram of at least one embodiment of a storage sled usable in the data center of FIG. 1;

FIG. 13 is a top perspective view of at least one embodiment of the storage sled of FIG. 12;

FIG. 14 is a simplified block diagram of at least one embodiment of a memory sled usable in the data center of FIG. 1; and

FIG. 15 is a simplified block diagram of a system that may be established within the data center of FIG. 1 to execute workloads with managed nodes composed of disaggregated resources.

FIG. 16 is a simplified block diagram of at least one embodiment of a system for latency based service level agreements in RDMA networks;

FIG. 17 is a simplified block diagram of at least one embodiment of an environment that may be established by a network switch of FIG. 16;

FIG. 18 is a simplified flow diagram of at least one embodiment of a method for monitoring RDMA latency that may be executed by a host compute device of FIGS. 16-17;

FIG. 19 is a simplified flow diagram of at least one embodiment of a method for priority scheduling RDMA requests that may be executed by a compute device of FIGS. 16-17; and

FIG. 20 is a simplified flow diagram of at least one embodiment of a method for managing switch queue resources that may be executed by a compute device of FIGS. 16-17.

DETAILED DESCRIPTION OF THE DRAWINGS

While the concepts of the present disclosure are susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and will be described herein in detail. It should be understood, however, that there is no intent to limit the concepts of the present disclosure to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives consistent with the present disclosure and the appended claims.

References in the specification to “one embodiment,” “an embodiment,” “an illustrative embodiment,” etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may or may not necessarily include that particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to effect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described. Additionally, it should be appreciated that items included in a list in the form of “at least one A, B, and C” can mean (A); (B); (C); (A and B); (A and C); (B and C); or (A, B, and C). Similarly, items listed in the form of “at least one of A, B, or C” can mean (A); (B); (C); (A and B); (A and C); (B and C); or (A, B, and C).

The disclosed embodiments may be implemented, in some cases, in hardware, firmware, software, or any combination thereof. The disclosed embodiments may also be implemented as instructions carried by or stored on a transitory or non-transitory machine-readable (e.g., computer-readable) storage medium, which may be read and executed by one or more processors. A machine-readable storage medium may be embodied as any storage device, mechanism, or other physical structure for storing or transmitting information in a form readable by a machine (e.g., a volatile or non-volatile memory, a media disc, or other media device).

In the drawings, some structural or method features may be shown in specific arrangements and/or orderings. However, it should be appreciated that such specific arrangements and/or orderings may not be required. Rather, in some embodiments, such features may be arranged in a different manner and/or order than shown in the illustrative figures. Additionally, the inclusion of a structural or method feature in a particular figure is not meant to imply that such feature is required in all embodiments and, in some embodiments, may not be included or may be combined with other features.

Referring now to FIG. 1, a data center 100 in which disaggregated resources may cooperatively execute one or more workloads (e.g., applications on behalf of customers) includes multiple pods 110, 120, 130, 140, each of which includes one or more rows of racks. Of course, although data center 100 is shown with multiple pods, in some embodiments, the data center 100 may be embodied as a single pod. As described in more detail herein, each rack houses multiple sleds, each of which may be primarily equipped with a particular type of resource (e.g., memory devices, data storage devices, accelerator devices, general purpose processors), i.e., resources that can be logically coupled to form a composed node, which can act as, for example, a server. In the illustrative embodiment, the sleds in each pod 110, 120, 130, 140 are connected to multiple pod switches (e.g., switches that route data communications to and from sleds within the pod). The pod switches, in turn, connect with spine switches 150 that switch communications among pods (e.g., the pods 110, 120, 130, 140) in the data center 100. In some embodiments, the sleds may be connected with a fabric using Intel Omni-Path technology. In other embodiments, the sleds may be connected with other fabrics, such as InfiniBand or Ethernet. As described in more detail herein, resources within sleds in the data center 100 may be allocated to a group (referred to herein as a “managed node”) containing resources from one or more sleds to be collectively utilized in the execution of a workload. The workload can execute as if the resources belonging to the managed node were located on the same sled. The resources in a managed node may belong to sleds belonging to different racks, and even to different pods 110, 120, 130, 140. As such, some resources of a single sled may be allocated to one managed node while other resources of the same sled are allocated to a different managed node (e.g., one processor assigned to one managed node and another processor of the same sled assigned to a different managed node).

A data center comprising disaggregated resources, such as data center 100, can be used in a wide variety of contexts, such as enterprise, government, cloud service provider, and communications service provider (e.g., Telco's), as well in a wide variety of sizes, from cloud service provider mega-data centers that consume over 100,000 sq. ft. to single- or multi-rack installations for use in base stations.

The disaggregation of resources to sleds comprised predominantly of a single type of resource (e.g., compute sleds comprising primarily compute resources, memory sleds containing primarily memory resources), and the selective allocation and deallocation of the disaggregated resources to form a managed node assigned to execute a workload improves the operation and resource usage of the data center 100 relative to typical data centers comprised of hyperconverged servers containing compute, memory, storage and perhaps additional resources in a single chassis. For example, because sleds predominantly contain resources of a particular type, resources of a given type can be upgraded independently of other resources. Additionally, because different resources types (processors, storage, accelerators, etc.) typically have different refresh rates, greater resource utilization and reduced total cost of ownership may be achieved. For example, a data center operator can upgrade the processors throughout their facility by only swapping out the compute sleds. In such a case, accelerator and storage resources may not be contemporaneously upgraded and, rather, may be allowed to continue operating until those resources are scheduled for their own refresh. Resource utilization may also increase. For example, if managed nodes are composed based on requirements of the workloads that will be running on them, resources within a node are more likely to be fully utilized. Such utilization may allow for more managed nodes to run in a data center with a given set of resources, or for a data center expected to run a given set of workloads, to be built using fewer resources.

Referring now to FIG. 2, the pod 110, in the illustrative embodiment, includes a set of rows 200, 210, 220, 230 of racks 240. Each rack 240 may house multiple sleds (e.g., sixteen sleds) and provide power and data connections to the housed sleds, as described in more detail herein. In the illustrative embodiment, the racks in each row 200, 210, 220, 230 are connected to multiple pod switches 250, 260. The pod switch 250 includes a set of ports 252 to which the sleds of the racks of the pod 110 are connected and another set of ports 254 that connect the pod 110 to the spine switches 150 to provide connectivity to other pods in the data center 100. Similarly, the pod switch 260 includes a set of ports 262 to which the sleds of the racks of the pod 110 are connected and a set of ports 264 that connect the pod 110 to the spine switches 150. As such, the use of the pair of switches 250, 260 provides an amount of redundancy to the pod 110. For example, if either of the switches 250, 260 fails, the sleds in the pod 110 may still maintain data communication with the remainder of the data center 100 (e.g., sleds of other pods) through the other switch 250, 260. Furthermore, in the illustrative embodiment, the switches 150, 250, 260 may be embodied as dual-mode optical switches, capable of routing both Ethernet protocol communications carrying Internet Protocol (IP) packets and communications according to a second, high-performance link-layer protocol (e.g., Intel's Omni-Path Architecture's, InfiniBand, PCI Express) via optical signaling media of an optical fabric.

It should be appreciated that each of the other pods 120, 130, 140 (as well as any additional pods of the data center 100) may be similarly structured as, and have components similar to, the pod 110 shown in and described in regard to FIG. 2 (e.g., each pod may have rows of racks housing multiple sleds as described above). Additionally, while two pod switches 250, 260 are shown, it should be understood that in other embodiments, each pod 110, 120, 130, 140 may be connected to a different number of pod switches, providing even more failover capacity. Of course, in other embodiments, pods may be arranged differently than the rows-of-racks configuration shown in FIGS. 1-2. For example, a pod may be embodied as multiple sets of racks in which each set of racks is arranged radially, i.e., the racks are equidistant from a center switch.

Referring now to FIGS. 3-5, each illustrative rack 240 of the data center 100 includes two elongated support posts 302, 304, which are arranged vertically. For example, the elongated support posts 302, 304 may extend upwardly from a floor of the data center 100 when deployed. The rack 240 also includes one or more horizontal pairs 310 of elongated support arms 312 (identified in FIG. 3 via a dashed ellipse) configured to support a sled of the data center 100 as discussed below. One elongated support arm 312 of the pair of elongated support arms 312 extends outwardly from the elongated support post 302 and the other elongated support arm 312 extends outwardly from the elongated support post 304.

In the illustrative embodiments, each sled of the data center 100 is embodied as a chassis-less sled. That is, each sled has a chassis-less circuit board substrate on which physical resources (e.g., processors, memory, accelerators, storage, etc.) are mounted as discussed in more detail below. As such, the rack 240 is configured to receive the chassis-less sleds. For example, each pair 310 of elongated support arms 312 defines a sled slot 320 of the rack 240, which is configured to receive a corresponding chassis-less sled. To do so, each illustrative elongated support arm 312 includes a circuit board guide 330 configured to receive the chassis-less circuit board substrate of the sled. Each circuit board guide 330 is secured to, or otherwise mounted to, a top side 332 of the corresponding elongated support arm 312. For example, in the illustrative embodiment, each circuit board guide 330 is mounted at a distal end of the corresponding elongated support arm 312 relative to the corresponding elongated support post 302, 304. For clarity of the Figures, not every circuit board guide 330 may be referenced in each Figure.

Each circuit board guide 330 includes an inner wall that defines a circuit board slot 380 configured to receive the chassis-less circuit board substrate of a sled 400 when the sled 400 is received in the corresponding sled slot 320 of the rack 240. To do so, as shown in FIG. 4, a user (or robot) aligns the chassis-less circuit board substrate of an illustrative chassis-less sled 400 to a sled slot 320. The user, or robot, may then slide the chassis-less circuit board substrate forward into the sled slot 320 such that each side edge 414 of the chassis-less circuit board substrate is received in a corresponding circuit board slot 380 of the circuit board guides 330 of the pair 310 of elongated support arms 312 that define the corresponding sled slot 320 as shown in FIG. 4. By having robotically accessible and robotically manipulable sleds comprising disaggregated resources, each type of resource can be upgraded independently of each other and at their own optimized refresh rate. Furthermore, the sleds are configured to blindly mate with power and data communication cables in each rack 240, enhancing their ability to be quickly removed, upgraded, reinstalled, and/or replaced. As such, in some embodiments, the data center 100 may operate (e.g., execute workloads, undergo maintenance and/or upgrades, etc.) without human involvement on the data center floor. In other embodiments, a human may facilitate one or more maintenance or upgrade operations in the data center 100.

It should be appreciated that each circuit board guide 330 is dual sided. That is, each circuit board guide 330 includes an inner wall that defines a circuit board slot 380 on each side of the circuit board guide 330. In this way, each circuit board guide 330 can support a chassis-less circuit board substrate on either side. As such, a single additional elongated support post may be added to the rack 240 to turn the rack 240 into a two-rack solution that can hold twice as many sled slots 320 as shown in FIG. 3. The illustrative rack 240 includes seven pairs 310 of elongated support arms 312 that define a corresponding seven sled slots 320, each configured to receive and support a corresponding sled 400 as discussed above. Of course, in other embodiments, the rack 240 may include additional or fewer pairs 310 of elongated support arms 312 (i.e., additional or fewer sled slots 320). It should be appreciated that because the sled 400 is chassis-less, the sled 400 may have an overall height that is different than typical servers. As such, in some embodiments, the height of each sled slot 320 may be shorter than the height of a typical server (e.g., shorter than a single rank unit, “1 U”). That is, the vertical distance between each pair 310 of elongated support arms 312 may be less than a standard rack unit “1 U.” Additionally, due to the relative decrease in height of the sled slots 320, the overall height of the rack 240 in some embodiments may be shorter than the height of traditional rack enclosures. For example, in some embodiments, each of the elongated support posts 302, 304 may have a length of six feet or less. Again, in other embodiments, the rack 240 may have different dimensions. For example, in some embodiments, the vertical distance between each pair 310 of elongated support arms 312 may be greater than a standard rack until “1 U”. In such embodiments, the increased vertical distance between the sleds allows for larger heat sinks to be attached to the physical resources and for larger fans to be used (e.g., in the fan array 370 described below) for cooling each sled, which in turn can allow the physical resources to operate at increased power levels. Further, it should be appreciated that the rack 240 does not include any walls, enclosures, or the like. Rather, the rack 240 is an enclosure-less rack that is opened to the local environment. Of course, in some cases, an end plate may be attached to one of the elongated support posts 302, 304 in those situations in which the rack 240 forms an end-of-row rack in the data center 100.

In some embodiments, various interconnects may be routed upwardly or downwardly through the elongated support posts 302, 304. To facilitate such routing, each elongated support post 302, 304 includes an inner wall that defines an inner chamber in which interconnects may be located. The interconnects routed through the elongated support posts 302, 304 may be embodied as any type of interconnects including, but not limited to, data or communication interconnects to provide communication connections to each sled slot 320, power interconnects to provide power to each sled slot 320, and/or other types of interconnects.

The rack 240, in the illustrative embodiment, includes a support platform on which a corresponding optical data connector (not shown) is mounted. Each optical data connector is associated with a corresponding sled slot 320 and is configured to mate with an optical data connector of a corresponding sled 400 when the sled 400 is received in the corresponding sled slot 320. In some embodiments, optical connections between components (e.g., sleds, racks, and switches) in the data center 100 are made with a blind mate optical connection. For example, a door on each cable may prevent dust from contaminating the fiber inside the cable. In the process of connecting to a blind mate optical connector mechanism, the door is pushed open when the end of the cable approaches or enters the connector mechanism. Subsequently, the optical fiber inside the cable may enter a gel within the connector mechanism and the optical fiber of one cable comes into contact with the optical fiber of another cable within the gel inside the connector mechanism.

The illustrative rack 240 also includes a fan array 370 coupled to the cross-support arms of the rack 240. The fan array 370 includes one or more rows of cooling fans 372, which are aligned in a horizontal line between the elongated support posts 302, 304. In the illustrative embodiment, the fan array 370 includes a row of cooling fans 372 for each sled slot 320 of the rack 240. As discussed above, each sled 400 does not include any on-board cooling system in the illustrative embodiment and, as such, the fan array 370 provides cooling for each sled 400 received in the rack 240. Each rack 240, in the illustrative embodiment, also includes a power supply associated with each sled slot 320. Each power supply is secured to one of the elongated support arms 312 of the pair 310 of elongated support arms 312 that define the corresponding sled slot 320. For example, the rack 240 may include a power supply coupled or secured to each elongated support arm 312 extending from the elongated support post 302. Each power supply includes a power connector configured to mate with a power connector of the sled 400 when the sled 400 is received in the corresponding sled slot 320. In the illustrative embodiment, the sled 400 does not include any on-board power supply and, as such, the power supplies provided in the rack 240 supply power to corresponding sleds 400 when mounted to the rack 240. Each power supply is configured to satisfy the power requirements for its associated sled, which can vary from sled to sled. Additionally, the power supplies provided in the rack 240 can operate independent of each other. That is, within a single rack, a first power supply providing power to a compute sled can provide power levels that are different than power levels supplied by a second power supply providing power to an accelerator sled. The power supplies may be controllable at the sled level or rack level, and may be controlled locally by components on the associated sled or remotely, such as by another sled or an orchestrator.

Referring now to FIG. 6, the sled 400, in the illustrative embodiment, is configured to be mounted in a corresponding rack 240 of the data center 100 as discussed above. In some embodiments, each sled 400 may be optimized or otherwise configured for performing particular tasks, such as compute tasks, acceleration tasks, data storage tasks, etc. For example, the sled 400 may be embodied as a compute sled 800 as discussed below in regard to FIGS. 8-9, an accelerator sled 1000 as discussed below in regard to FIGS. 10-11, a storage sled 1200 as discussed below in regard to FIGS. 12-13, or as a sled optimized or otherwise configured to perform other specialized tasks, such as a memory sled 1400, discussed below in regard to FIG. 14.

As discussed above, the illustrative sled 400 includes a chassis-less circuit board substrate 602, which supports various physical resources (e.g., electrical components) mounted thereon. It should be appreciated that the circuit board substrate 602 is “chassis-less” in that the sled 400 does not include a housing or enclosure. Rather, the chassis-less circuit board substrate 602 is open to the local environment. The chassis-less circuit board substrate 602 may be formed from any material capable of supporting the various electrical components mounted thereon. For example, in an illustrative embodiment, the chassis-less circuit board substrate 602 is formed from an FR-4 glass-reinforced epoxy laminate material. Of course, other materials may be used to form the chassis-less circuit board substrate 602 in other embodiments.

As discussed in more detail below, the chassis-less circuit board substrate 602 includes multiple features that improve the thermal cooling characteristics of the various electrical components mounted on the chassis-less circuit board substrate 602. As discussed, the chassis-less circuit board substrate 602 does not include a housing or enclosure, which may improve the airflow over the electrical components of the sled 400 by reducing those structures that may inhibit air flow. For example, because the chassis-less circuit board substrate 602 is not positioned in an individual housing or enclosure, there is no vertically-arranged backplane (e.g., a backplate of the chassis) attached to the chassis-less circuit board substrate 602, which could inhibit air flow across the electrical components. Additionally, the chassis-less circuit board substrate 602 has a geometric shape configured to reduce the length of the airflow path across the electrical components mounted to the chassis-less circuit board substrate 602. For example, the illustrative chassis-less circuit board substrate 602 has a width 604 that is greater than a depth 606 of the chassis-less circuit board substrate 602. In one particular embodiment, for example, the chassis-less circuit board substrate 602 has a width of about 21 inches and a depth of about 9 inches, compared to a typical server that has a width of about 17 inches and a depth of about 39 inches. As such, an airflow path 608 that extends from a front edge 610 of the chassis-less circuit board substrate 602 toward a rear edge 612 has a shorter distance relative to typical servers, which may improve the thermal cooling characteristics of the sled 400. Furthermore, although not illustrated in FIG. 6, the various physical resources mounted to the chassis-less circuit board substrate 602 are mounted in corresponding locations such that no two substantively heat-producing electrical components shadow each other as discussed in more detail below. That is, no two electrical components, which produce appreciable heat during operation (i.e., greater than a nominal heat sufficient enough to adversely impact the cooling of another electrical component), are mounted to the chassis-less circuit board substrate 602 linearly in-line with each other along the direction of the airflow path 608 (i.e., along a direction extending from the front edge 610 toward the rear edge 612 of the chassis-less circuit board substrate 602).

As discussed above, the illustrative sled 400 includes one or more physical resources 620 mounted to a top side 650 of the chassis-less circuit board substrate 602. Although two physical resources 620 are shown in FIG. 6, it should be appreciated that the sled 400 may include one, two, or more physical resources 620 in other embodiments. The physical resources 620 may be embodied as any type of processor, controller, or other compute circuit capable of performing various tasks such as compute functions and/or controlling the functions of the sled 400 depending on, for example, the type or intended functionality of the sled 400. For example, as discussed in more detail below, the physical resources 620 may be embodied as high-performance processors in embodiments in which the sled 400 is embodied as a compute sled, as accelerator co-processors or circuits in embodiments in which the sled 400 is embodied as an accelerator sled, storage controllers in embodiments in which the sled 400 is embodied as a storage sled, or a set of memory devices in embodiments in which the sled 400 is embodied as a memory sled.

The sled 400 also includes one or more additional physical resources 630 mounted to the top side 650 of the chassis-less circuit board substrate 602. In the illustrative embodiment, the additional physical resources include a network interface controller (NIC) as discussed in more detail below. Of course, depending on the type and functionality of the sled 400, the physical resources 630 may include additional or other electrical components, circuits, and/or devices in other embodiments.

The physical resources 620 are communicatively coupled to the physical resources 630 via an input/output (I/O) subsystem 622. The I/O subsystem 622 may be embodied as circuitry and/or components to facilitate input/output operations with the physical resources 620, the physical resources 630, and/or other components of the sled 400. For example, the I/O subsystem 622 may be embodied as, or otherwise include, memory controller hubs, input/output control hubs, integrated sensor hubs, firmware devices, communication links (e.g., point-to-point links, bus links, wires, cables, waveguides, light guides, printed circuit board traces, etc.), and/or other components and subsystems to facilitate the input/output operations. In the illustrative embodiment, the I/O subsystem 622 is embodied as, or otherwise includes, a double data rate 4 (DDR4) data bus or a DDR5 data bus.

In some embodiments, the sled 400 may also include a resource-to-resource interconnect 624. The resource-to-resource interconnect 624 may be embodied as any type of communication interconnect capable of facilitating resource-to-resource communications. In the illustrative embodiment, the resource-to-resource interconnect 624 is embodied as a high-speed point-to-point interconnect (e.g., faster than the I/O subsystem 622). For example, the resource-to-resource interconnect 624 may be embodied as a QuickPath Interconnect (QPI), an UltraPath Interconnect (UPI), or other high-speed point-to-point interconnect dedicated to resource-to-resource communications.

The sled 400 also includes a power connector 640 configured to mate with a corresponding power connector of the rack 240 when the sled 400 is mounted in the corresponding rack 240. The sled 400 receives power from a power supply of the rack 240 via the power connector 640 to supply power to the various electrical components of the sled 400. That is, the sled 400 does not include any local power supply (i.e., an on-board power supply) to provide power to the electrical components of the sled 400. The exclusion of a local or on-board power supply facilitates the reduction in the overall footprint of the chassis-less circuit board substrate 602, which may increase the thermal cooling characteristics of the various electrical components mounted on the chassis-less circuit board substrate 602 as discussed above. In some embodiments, voltage regulators are placed on a bottom side 750 (see FIG. 7) of the chassis-less circuit board substrate 602 directly opposite of the processors 820 (see FIG. 8), and power is routed from the voltage regulators to the processors 820 by vias extending through the circuit board substrate 602. Such a configuration provides an increased thermal budget, additional current and/or voltage, and better voltage control relative to typical printed circuit boards in which processor power is delivered from a voltage regulator, in part, by printed circuit traces.

In some embodiments, the sled 400 may also include mounting features 642 configured to mate with a mounting arm, or other structure, of a robot to facilitate the placement of the sled 600 in a rack 240 by the robot. The mounting features 642 may be embodied as any type of physical structures that allow the robot to grasp the sled 400 without damaging the chassis-less circuit board substrate 602 or the electrical components mounted thereto. For example, in some embodiments, the mounting features 642 may be embodied as non-conductive pads attached to the chassis-less circuit board substrate 602. In other embodiments, the mounting features may be embodied as brackets, braces, or other similar structures attached to the chassis-less circuit board substrate 602. The particular number, shape, size, and/or make-up of the mounting feature 642 may depend on the design of the robot configured to manage the sled 400.

Referring now to FIG. 7, in addition to the physical resources 630 mounted on the top side 650 of the chassis-less circuit board substrate 602, the sled 400 also includes one or more memory devices 720 mounted to a bottom side 750 of the chassis-less circuit board substrate 602. That is, the chassis-less circuit board substrate 602 is embodied as a double-sided circuit board. The physical resources 620 are communicatively coupled to the memory devices 720 via the I/O subsystem 622. For example, the physical resources 620 and the memory devices 720 may be communicatively coupled by one or more vias extending through the chassis-less circuit board substrate 602. Each physical resource 620 may be communicatively coupled to a different set of one or more memory devices 720 in some embodiments. Alternatively, in other embodiments, each physical resource 620 may be communicatively coupled to each memory device 720.

The memory devices 720 may be embodied as any type of memory device capable of storing data for the physical resources 620 during operation of the sled 400, such as any type of volatile (e.g., dynamic random access memory (DRAM), etc.) or non-volatile memory. Volatile memory may be a storage medium that requires power to maintain the state of data stored by the medium. Non-limiting examples of volatile memory may include various types of random access memory (RAM), such as dynamic random access memory (DRAM) or static random access memory (SRAM). One particular type of DRAM that may be used in a memory module is synchronous dynamic random access memory (SDRAM). In particular embodiments, DRAM of a memory component may comply with a standard promulgated by JEDEC, such as JESD79F for DDR SDRAM, JESD79-2F for DDR2 SDRAM, JESD79-3F for DDR3 SDRAM, JESD79-4A for DDR4 SDRAM, JESD209 for Low Power DDR (LPDDR), JESD209-2 for LPDDR2, JESD209-3 for LPDDR3, and JESD209-4 for LPDDR4. Such standards (and similar standards) may be referred to as DDR-based standards and communication interfaces of the storage devices that implement such standards may be referred to as DDR-based interfaces.

In one embodiment, the memory device is a block addressable memory device, such as those based on NAND or NOR technologies. A memory device may also include next-generation nonvolatile devices, such as Intel 3D XPoint™ memory or other byte addressable write-in-place nonvolatile memory devices. In one embodiment, the memory device may be or may include memory devices that use chalcogenide glass, multi-threshold level NAND flash memory, NOR flash memory, single or multi-level Phase Change Memory (PCM), a resistive memory, nanowire memory, ferroelectric transistor random access memory (FeTRAM), anti-ferroelectric memory, magnetoresistive random access memory (MRAM) memory that incorporates memristor technology, resistive memory including the metal oxide base, the oxygen vacancy base and the conductive bridge Random Access Memory (CB-RAM), or spin transfer torque (STT)-MRAM, a spintronic magnetic junction memory based device, a magnetic tunneling junction (MTJ) based device, a DW (Domain Wall) and SOT (Spin Orbit Transfer) based device, a thyristor based memory device, or a combination of any of the above, or other memory. The memory device may refer to the die itself and/or to a packaged memory product. In some embodiments, the memory device may comprise a transistor-less stackable cross point architecture in which memory cells sit at the intersection of word lines and bit lines and are individually addressable and in which bit storage is based on a change in bulk resistance.

Referring now to FIG. 8, in some embodiments, the sled 400 may be embodied as a compute sled 800. The compute sled 800 is optimized, or otherwise configured, to perform compute tasks. Of course, as discussed above, the compute sled 800 may rely on other sleds, such as acceleration sleds and/or storage sleds, to perform such compute tasks. The compute sled 800 includes various physical resources (e.g., electrical components) similar to the physical resources of the sled 400, which have been identified in FIG. 8 using the same reference numbers. The description of such components provided above in regard to FIGS. 6 and 7 applies to the corresponding components of the compute sled 800 and is not repeated herein for clarity of the description of the compute sled 800.

In the illustrative compute sled 800, the physical resources 620 are embodied as processors 820. Although only two processors 820 are shown in FIG. 8, it should be appreciated that the compute sled 800 may include additional processors 820 in other embodiments. Illustratively, the processors 820 are embodied as high-performance processors 820 and may be configured to operate at a relatively high power rating. Although the processors 820 generate additional heat operating at power ratings greater than typical processors (which operate at around 155-230 W), the enhanced thermal cooling characteristics of the chassis-less circuit board substrate 602 discussed above facilitate the higher power operation. For example, in the illustrative embodiment, the processors 820 are configured to operate at a power rating of at least 250 W. In some embodiments, the processors 820 may be configured to operate at a power rating of at least 350 W.

In some embodiments, the compute sled 800 may also include a processor-to-processor interconnect 842. Similar to the resource-to-resource interconnect 624 of the sled 400 discussed above, the processor-to-processor interconnect 842 may be embodied as any type of communication interconnect capable of facilitating processor-to-processor interconnect 842 communications. In the illustrative embodiment, the processor-to-processor interconnect 842 is embodied as a high-speed point-to-point interconnect (e.g., faster than the I/O subsystem 622). For example, the processor-to-processor interconnect 842 may be embodied as a QuickPath Interconnect (QPI), an UltraPath Interconnect (UPI), or other high-speed point-to-point interconnect dedicated to processor-to-processor communications.

The compute sled 800 also includes a communication circuit 830. The illustrative communication circuit 830 includes a network interface controller (NIC) 832, which may also be referred to as a host fabric interface (HFI). The NIC 832 may be embodied as, or otherwise include, any type of integrated circuit, discrete circuits, controller chips, chipsets, add-in-boards, daughtercards, network interface cards, or other devices that may be used by the compute sled 800 to connect with another compute device (e.g., with other sleds 400). In some embodiments, the NIC 832 may be embodied as part of a system-on-a-chip (SoC) that includes one or more processors, or included on a multichip package that also contains one or more processors. In some embodiments, the NIC 832 may include a local processor (not shown) and/or a local memory (not shown) that are both local to the NIC 832. In such embodiments, the local processor of the NIC 832 may be capable of performing one or more of the functions of the processors 820. Additionally or alternatively, in such embodiments, the local memory of the NIC 832 may be integrated into one or more components of the compute sled at the board level, socket level, chip level, and/or other levels.

The communication circuit 830 is communicatively coupled to an optical data connector 834. The optical data connector 834 is configured to mate with a corresponding optical data connector of the rack 240 when the compute sled 800 is mounted in the rack 240. Illustratively, the optical data connector 834 includes a plurality of optical fibers which lead from a mating surface of the optical data connector 834 to an optical transceiver 836. The optical transceiver 836 is configured to convert incoming optical signals from the rack-side optical data connector to electrical signals and to convert electrical signals to outgoing optical signals to the rack-side optical data connector. Although shown as forming part of the optical data connector 834 in the illustrative embodiment, the optical transceiver 836 may form a portion of the communication circuit 830 in other embodiments.

In some embodiments, the compute sled 800 may also include an expansion connector 840. In such embodiments, the expansion connector 840 is configured to mate with a corresponding connector of an expansion chassis-less circuit board substrate to provide additional physical resources to the compute sled 800. The additional physical resources may be used, for example, by the processors 820 during operation of the compute sled 800. The expansion chassis-less circuit board substrate may be substantially similar to the chassis-less circuit board substrate 602 discussed above and may include various electrical components mounted thereto. The particular electrical components mounted to the expansion chassis-less circuit board substrate may depend on the intended functionality of the expansion chassis-less circuit board substrate. For example, the expansion chassis-less circuit board substrate may provide additional compute resources, memory resources, and/or storage resources. As such, the additional physical resources of the expansion chassis-less circuit board substrate may include, but is not limited to, processors, memory devices, storage devices, and/or accelerator circuits including, for example, field programmable gate arrays (FPGA), application-specific integrated circuits (ASICs), security co-processors, graphics processing units (GPUs), machine learning circuits, or other specialized processors, controllers, devices, and/or circuits.

Referring now to FIG. 9, an illustrative embodiment of the compute sled 800 is shown. As shown, the processors 820, communication circuit 830, and optical data connector 834 are mounted to the top side 650 of the chassis-less circuit board substrate 602. Any suitable attachment or mounting technology may be used to mount the physical resources of the compute sled 800 to the chassis-less circuit board substrate 602. For example, the various physical resources may be mounted in corresponding sockets (e.g., a processor socket), holders, or brackets. In some cases, some of the electrical components may be directly mounted to the chassis-less circuit board substrate 602 via soldering or similar techniques.

As discussed above, the individual processors 820 and communication circuit 830 are mounted to the top side 650 of the chassis-less circuit board substrate 602 such that no two heat-producing, electrical components shadow each other. In the illustrative embodiment, the processors 820 and communication circuit 830 are mounted in corresponding locations on the top side 650 of the chassis-less circuit board substrate 602 such that no two of those physical resources are linearly in-line with others along the direction of the airflow path 608. It should be appreciated that, although the optical data connector 834 is in-line with the communication circuit 830, the optical data connector 834 produces no or nominal heat during operation.

The memory devices 720 of the compute sled 800 are mounted to the bottom side 750 of the of the chassis-less circuit board substrate 602 as discussed above in regard to the sled 400. Although mounted to the bottom side 750, the memory devices 720 are communicatively coupled to the processors 820 located on the top side 650 via the I/O subsystem 622. Because the chassis-less circuit board substrate 602 is embodied as a double-sided circuit board, the memory devices 720 and the processors 820 may be communicatively coupled by one or more vias, connectors, or other mechanisms extending through the chassis-less circuit board substrate 602. Of course, each processor 820 may be communicatively coupled to a different set of one or more memory devices 720 in some embodiments. Alternatively, in other embodiments, each processor 820 may be communicatively coupled to each memory device 720. In some embodiments, the memory devices 720 may be mounted to one or more memory mezzanines on the bottom side of the chassis-less circuit board substrate 602 and may interconnect with a corresponding processor 820 through a ball-grid array.

Each of the processors 820 includes a heatsink 850 secured thereto. Due to the mounting of the memory devices 720 to the bottom side 750 of the chassis-less circuit board substrate 602 (as well as the vertical spacing of the sleds 400 in the corresponding rack 240), the top side 650 of the chassis-less circuit board substrate 602 includes additional “free” area or space that facilitates the use of heatsinks 850 having a larger size relative to traditional heatsinks used in typical servers. Additionally, due to the improved thermal cooling characteristics of the chassis-less circuit board substrate 602, none of the processor heatsinks 850 include cooling fans attached thereto. That is, each of the heatsinks 850 is embodied as a fan-less heatsink. In some embodiments, the heat sinks 850 mounted atop the processors 820 may overlap with the heat sink attached to the communication circuit 830 in the direction of the airflow path 608 due to their increased size, as illustratively suggested by FIG. 9.

Referring now to FIG. 10, in some embodiments, the sled 400 may be embodied as an accelerator sled 1000. The accelerator sled 1000 is configured, to perform specialized compute tasks, such as machine learning, encryption, hashing, or other computational-intensive task. In some embodiments, for example, a compute sled 800 may offload tasks to the accelerator sled 1000 during operation. The accelerator sled 1000 includes various components similar to components of the sled 400 and/or compute sled 800, which have been identified in FIG. 10 using the same reference numbers. The description of such components provided above in regard to FIGS. 6, 7, and 8 apply to the corresponding components of the accelerator sled 1000 and is not repeated herein for clarity of the description of the accelerator sled 1000.

In the illustrative accelerator sled 1000, the physical resources 620 are embodied as accelerator circuits 1020. Although only two accelerator circuits 1020 are shown in FIG. 10, it should be appreciated that the accelerator sled 1000 may include additional accelerator circuits 1020 in other embodiments. For example, as shown in FIG. 11, the accelerator sled 1000 may include four accelerator circuits 1020 in some embodiments. The accelerator circuits 1020 may be embodied as any type of processor, co-processor, compute circuit, or other device capable of performing compute or processing operations. For example, the accelerator circuits 1020 may be embodied as, for example, field programmable gate arrays (FPGA), application-specific integrated circuits (ASICs), security co-processors, graphics processing units (GPUs), neuromorphic processor units, quantum computers, machine learning circuits, or other specialized processors, controllers, devices, and/or circuits.

In some embodiments, the accelerator sled 1000 may also include an accelerator-to-accelerator interconnect 1042. Similar to the resource-to-resource interconnect 624 of the sled 600 discussed above, the accelerator-to-accelerator interconnect 1042 may be embodied as any type of communication interconnect capable of facilitating accelerator-to-accelerator communications. In the illustrative embodiment, the accelerator-to-accelerator interconnect 1042 is embodied as a high-speed point-to-point interconnect (e.g., faster than the I/O subsystem 622). For example, the accelerator-to-accelerator interconnect 1042 may be embodied as a QuickPath Interconnect (QPI), an UltraPath Interconnect (UPI), or other high-speed point-to-point interconnect dedicated to processor-to-processor communications. In some embodiments, the accelerator circuits 1020 may be daisy-chained with a primary accelerator circuit 1020 connected to the NIC 832 and memory 720 through the I/O subsystem 622 and a secondary accelerator circuit 1020 connected to the NIC 832 and memory 720 through a primary accelerator circuit 1020.

Referring now to FIG. 11, an illustrative embodiment of the accelerator sled 1000 is shown. As discussed above, the accelerator circuits 1020, communication circuit 830, and optical data connector 834 are mounted to the top side 650 of the chassis-less circuit board substrate 602. Again, the individual accelerator circuits 1020 and communication circuit 830 are mounted to the top side 650 of the chassis-less circuit board substrate 602 such that no two heat-producing, electrical components shadow each other as discussed above. The memory devices 720 of the accelerator sled 1000 are mounted to the bottom side 750 of the of the chassis-less circuit board substrate 602 as discussed above in regard to the sled 600. Although mounted to the bottom side 750, the memory devices 720 are communicatively coupled to the accelerator circuits 1020 located on the top side 650 via the I/O subsystem 622 (e.g., through vias). Further, each of the accelerator circuits 1020 may include a heatsink 1070 that is larger than a traditional heatsink used in a server. As discussed above with reference to the heatsinks 870, the heatsinks 1070 may be larger than traditional heatsinks because of the “free” area provided by the memory resources 720 being located on the bottom side 750 of the chassis-less circuit board substrate 602 rather than on the top side 650.

Referring now to FIG. 12, in some embodiments, the sled 400 may be embodied as a storage sled 1200. The storage sled 1200 is configured, to store data in a data storage 1250 local to the storage sled 1200. For example, during operation, a compute sled 800 or an accelerator sled 1000 may store and retrieve data from the data storage 1250 of the storage sled 1200. The storage sled 1200 includes various components similar to components of the sled 400 and/or the compute sled 800, which have been identified in FIG. 12 using the same reference numbers. The description of such components provided above in regard to FIGS. 6, 7, and 8 apply to the corresponding components of the storage sled 1200 and is not repeated herein for clarity of the description of the storage sled 1200.

In the illustrative storage sled 1200, the physical resources 620 are embodied as storage controllers 1220. Although only two storage controllers 1220 are shown in FIG. 12, it should be appreciated that the storage sled 1200 may include additional storage controllers 1220 in other embodiments. The storage controllers 1220 may be embodied as any type of processor, controller, or control circuit capable of controlling the storage and retrieval of data into the data storage 1250 based on requests received via the communication circuit 830. In the illustrative embodiment, the storage controllers 1220 are embodied as relatively low-power processors or controllers. For example, in some embodiments, the storage controllers 1220 may be configured to operate at a power rating of about 75 watts.

In some embodiments, the storage sled 1200 may also include a controller-to-controller interconnect 1242. Similar to the resource-to-resource interconnect 624 of the sled 400 discussed above, the controller-to-controller interconnect 1242 may be embodied as any type of communication interconnect capable of facilitating controller-to-controller communications. In the illustrative embodiment, the controller-to-controller interconnect 1242 is embodied as a high-speed point-to-point interconnect (e.g., faster than the I/O subsystem 622). For example, the controller-to-controller interconnect 1242 may be embodied as a QuickPath Interconnect (QPI), an UltraPath Interconnect (UPI), or other high-speed point-to-point interconnect dedicated to processor-to-processor communications.

Referring now to FIG. 13, an illustrative embodiment of the storage sled 1200 is shown. In the illustrative embodiment, the data storage 1250 is embodied as, or otherwise includes, a storage cage 1252 configured to house one or more solid state drives (SSDs) 1254. To do so, the storage cage 1252 includes a number of mounting slots 1256, each of which is configured to receive a corresponding solid state drive 1254. Each of the mounting slots 1256 includes a number of drive guides 1258 that cooperate to define an access opening 1260 of the corresponding mounting slot 1256. The storage cage 1252 is secured to the chassis-less circuit board substrate 602 such that the access openings face away from (i.e., toward the front of) the chassis-less circuit board substrate 602. As such, solid state drives 1254 are accessible while the storage sled 1200 is mounted in a corresponding rack 204. For example, a solid state drive 1254 may be swapped out of a rack 240 (e.g., via a robot) while the storage sled 1200 remains mounted in the corresponding rack 240.

The storage cage 1252 illustratively includes sixteen mounting slots 1256 and is capable of mounting and storing sixteen solid state drives 1254. Of course, the storage cage 1252 may be configured to store additional or fewer solid state drives 1254 in other embodiments. Additionally, in the illustrative embodiment, the solid state drivers are mounted vertically in the storage cage 1252, but may be mounted in the storage cage 1252 in a different orientation in other embodiments. Each solid state drive 1254 may be embodied as any type of data storage device capable of storing long term data. To do so, the solid state drives 1254 may include volatile and non-volatile memory devices discussed above.

As shown in FIG. 13, the storage controllers 1220, the communication circuit 830, and the optical data connector 834 are illustratively mounted to the top side 650 of the chassis-less circuit board substrate 602. Again, as discussed above, any suitable attachment or mounting technology may be used to mount the electrical components of the storage sled 1200 to the chassis-less circuit board substrate 602 including, for example, sockets (e.g., a processor socket), holders, brackets, soldered connections, and/or other mounting or securing techniques.

As discussed above, the individual storage controllers 1220 and the communication circuit 830 are mounted to the top side 650 of the chassis-less circuit board substrate 602 such that no two heat-producing, electrical components shadow each other. For example, the storage controllers 1220 and the communication circuit 830 are mounted in corresponding locations on the top side 650 of the chassis-less circuit board substrate 602 such that no two of those electrical components are linearly in-line with each other along the direction of the airflow path 608.

The memory devices 720 of the storage sled 1200 are mounted to the bottom side 750 of the of the chassis-less circuit board substrate 602 as discussed above in regard to the sled 400. Although mounted to the bottom side 750, the memory devices 720 are communicatively coupled to the storage controllers 1220 located on the top side 650 via the I/O subsystem 622. Again, because the chassis-less circuit board substrate 602 is embodied as a double-sided circuit board, the memory devices 720 and the storage controllers 1220 may be communicatively coupled by one or more vias, connectors, or other mechanisms extending through the chassis-less circuit board substrate 602. Each of the storage controllers 1220 includes a heatsink 1270 secured thereto. As discussed above, due to the improved thermal cooling characteristics of the chassis-less circuit board substrate 602 of the storage sled 1200, none of the heatsinks 1270 include cooling fans attached thereto. That is, each of the heatsinks 1270 is embodied as a fan-less heatsink.

Referring now to FIG. 14, in some embodiments, the sled 400 may be embodied as a memory sled 1400. The storage sled 1400 is optimized, or otherwise configured, to provide other sleds 400 (e.g., compute sleds 800, accelerator sleds 1000, etc.) with access to a pool of memory (e.g., in two or more sets 1430, 1432 of memory devices 720) local to the memory sled 1200. For example, during operation, a compute sled 800 or an accelerator sled 1000 may remotely write to and/or read from one or more of the memory sets 1430, 1432 of the memory sled 1200 using a logical address space that maps to physical addresses in the memory sets 1430, 1432. The memory sled 1400 includes various components similar to components of the sled 400 and/or the compute sled 800, which have been identified in FIG. 14 using the same reference numbers. The description of such components provided above in regard to FIGS. 6, 7, and 8 apply to the corresponding components of the memory sled 1400 and is not repeated herein for clarity of the description of the memory sled 1400.

In the illustrative memory sled 1400, the physical resources 620 are embodied as memory controllers 1420. Although only two memory controllers 1420 are shown in FIG. 14, it should be appreciated that the memory sled 1400 may include additional memory controllers 1420 in other embodiments. The memory controllers 1420 may be embodied as any type of processor, controller, or control circuit capable of controlling the writing and reading of data into the memory sets 1430, 1432 based on requests received via the communication circuit 830. In the illustrative embodiment, each memory controller 1420 is connected to a corresponding memory set 1430, 1432 to write to and read from memory devices 720 within the corresponding memory set 1430, 1432 and enforce any permissions (e.g., read, write, etc.) associated with sled 400 that has sent a request to the memory sled 1400 to perform a memory access operation (e.g., read or write).

In some embodiments, the memory sled 1400 may also include a controller-to-controller interconnect 1442. Similar to the resource-to-resource interconnect 624 of the sled 400 discussed above, the controller-to-controller interconnect 1442 may be embodied as any type of communication interconnect capable of facilitating controller-to-controller communications. In the illustrative embodiment, the controller-to-controller interconnect 1442 is embodied as a high-speed point-to-point interconnect (e.g., faster than the I/O subsystem 622). For example, the controller-to-controller interconnect 1442 may be embodied as a QuickPath Interconnect (QPI), an UltraPath Interconnect (UPI), or other high-speed point-to-point interconnect dedicated to processor-to-processor communications. As such, in some embodiments, a memory controller 1420 may access, through the controller-to-controller interconnect 1442, memory that is within the memory set 1432 associated with another memory controller 1420. In some embodiments, a scalable memory controller is made of multiple smaller memory controllers, referred to herein as “chiplets”, on a memory sled (e.g., the memory sled 1400). The chiplets may be interconnected (e.g., using EMIB (Embedded Multi-Die Interconnect Bridge)). The combined chiplet memory controller may scale up to a relatively large number of memory controllers and I/O ports, (e.g., up to 16 memory channels). In some embodiments, the memory controllers 1420 may implement a memory interleave (e.g., one memory address is mapped to the memory set 1430, the next memory address is mapped to the memory set 1432, and the third address is mapped to the memory set 1430, etc.). The interleaving may be managed within the memory controllers 1420, or from CPU sockets (e.g., of the compute sled 800) across network links to the memory sets 1430, 1432, and may improve the latency associated with performing memory access operations as compared to accessing contiguous memory addresses from the same memory device.

Further, in some embodiments, the memory sled 1400 may be connected to one or more other sleds 400 (e.g., in the same rack 240 or an adjacent rack 240) through a waveguide, using the waveguide connector 1480. In the illustrative embodiment, the waveguides are 64 millimeter waveguides that provide 16 Rx (i.e., receive) lanes and 16 Tx (i.e., transmit) lanes. Each lane, in the illustrative embodiment, is either 16 GHz or 32 GHz. In other embodiments, the frequencies may be different. Using a waveguide may provide high throughput access to the memory pool (e.g., the memory sets 1430, 1432) to another sled (e.g., a sled 400 in the same rack 240 or an adjacent rack 240 as the memory sled 1400) without adding to the load on the optical data connector 834.

Referring now to FIG. 15, a system for executing one or more workloads (e.g., applications) may be implemented in accordance with the data center 100. In the illustrative embodiment, the system 1510 includes an orchestrator server 1520, which may be embodied as a managed node comprising a compute device (e.g., a processor 820 on a compute sled 800) executing management software (e.g., a cloud operating environment, such as OpenStack) that is communicatively coupled to multiple sleds 400 including a large number of compute sleds 1530 (e.g., each similar to the compute sled 800), memory sleds 1540 (e.g., each similar to the memory sled 1400), accelerator sleds 1550 (e.g., each similar to the memory sled 1000), and storage sleds 1560 (e.g., each similar to the storage sled 1200). One or more of the sleds 1530, 1540, 1550, 1560 may be grouped into a managed node 1570, such as by the orchestrator server 1520, to collectively perform a workload (e.g., an application 1532 executed in a virtual machine or in a container). The managed node 1570 may be embodied as an assembly of physical resources 620, such as processors 820, memory resources 720, accelerator circuits 1020, or data storage 1250, from the same or different sleds 400. Further, the managed node may be established, defined, or “spun up” by the orchestrator server 1520 at the time a workload is to be assigned to the managed node or at any other time, and may exist regardless of whether any workloads are presently assigned to the managed node. In the illustrative embodiment, the orchestrator server 1520 may selectively allocate and/or deallocate physical resources 620 from the sleds 400 and/or add or remove one or more sleds 400 from the managed node 1570 as a function of quality of service (QoS) targets (e.g., performance targets associated with a throughput, latency, instructions per second, etc.) associated with a service level agreement for the workload (e.g., the application 1532). In doing so, the orchestrator server 1520 may receive telemetry data indicative of performance conditions (e.g., throughput, latency, instructions per second, etc.) in each sled 400 of the managed node 1570 and compare the telemetry data to the quality of service targets to determine whether the quality of service targets are being satisfied. The orchestrator server 1520 may additionally determine whether one or more physical resources may be deallocated from the managed node 1570 while still satisfying the QoS targets, thereby freeing up those physical resources for use in another managed node (e.g., to execute a different workload). Alternatively, if the QoS targets are not presently satisfied, the orchestrator server 1520 may determine to dynamically allocate additional physical resources to assist in the execution of the workload (e.g., the application 1532) while the workload is executing. Similarly, the orchestrator server 1520 may determine to dynamically deallocate physical resources from a managed node if the orchestrator server 1520 determines that deallocating the physical resource would result in QoS targets still being met.

Additionally, in some embodiments, the orchestrator server 1520 may identify trends in the resource utilization of the workload (e.g., the application 1532), such as by identifying phases of execution (e.g., time periods in which different operations, each having different resource utilizations characteristics, are performed) of the workload (e.g., the application 1532) and pre-emptively identifying available resources in the data center 100 and allocating them to the managed node 1570 (e.g., within a predefined time period of the associated phase beginning). In some embodiments, the orchestrator server 1520 may model performance based on various latencies and a distribution scheme to place workloads among compute sleds and other resources (e.g., accelerator sleds, memory sleds, storage sleds) in the data center 100. For example, the orchestrator server 1520 may utilize a model that accounts for the performance of resources on the sleds 400 (e.g., FPGA performance, memory access latency, etc.) and the performance (e.g., congestion, latency, bandwidth) of the path through the network to the resource (e.g., FPGA). As such, the orchestrator server 1520 may determine which resource(s) should be used with which workloads based on the total latency associated with each potential resource available in the data center 100 (e.g., the latency associated with the performance of the resource itself in addition to the latency associated with the path through the network between the compute sled executing the workload and the sled 400 on which the resource is located).

In some embodiments, the orchestrator server 1520 may generate a map of heat generation in the data center 100 using telemetry data (e.g., temperatures, fan speeds, etc.) reported from the sleds 400 and allocate resources to managed nodes as a function of the map of heat generation and predicted heat generation associated with different workloads, to maintain a target temperature and heat distribution in the data center 100. Additionally or alternatively, in some embodiments, the orchestrator server 1520 may organize received telemetry data into a hierarchical model that is indicative of a relationship between the managed nodes (e.g., a spatial relationship such as the physical locations of the resources of the managed nodes within the data center 100 and/or a functional relationship, such as groupings of the managed nodes by the customers the managed nodes provide services for, the types of functions typically performed by the managed nodes, managed nodes that typically share or exchange workloads among each other, etc.). Based on differences in the physical locations and resources in the managed nodes, a given workload may exhibit different resource utilizations (e.g., cause a different internal temperature, use a different percentage of processor or memory capacity) across the resources of different managed nodes. The orchestrator server 1520 may determine the differences based on the telemetry data stored in the hierarchical model and factor the differences into a prediction of future resource utilization of a workload if the workload is reassigned from one managed node to another managed node, to accurately balance resource utilization in the data center 100.

To reduce the computational load on the orchestrator server 1520 and the data transfer load on the network, in some embodiments, the orchestrator server 1520 may send self-test information to the sleds 400 to enable each sled 400 to locally (e.g., on the sled 400) determine whether telemetry data generated by the sled 400 satisfies one or more conditions (e.g., an available capacity that satisfies a predefined threshold, a temperature that satisfies a predefined threshold, etc.). Each sled 400 may then report back a simplified result (e.g., yes or no) to the orchestrator server 1520, which the orchestrator server 1520 may utilize in determining the allocation of resources to managed nodes.

Referring now to FIG. 16, an illustrative system 1600 for latency based service level agreements includes a controller device 1602 and multiple host devices 1604 in communication over a network 1606. In use, as described further below, one or more service level objectives (SLOs) are defined for RDMA networks. The system 1600 uses a latency-based calculation to measure RDMA requests against the SLO. Counters at the network interface controller (NIC) of the host devices 1604 may assist in latency calculations. The system 1600 uses flexible buffer management to meet the SLO based on how much deviation needs to be corrected to meet the SLO. Thus, the system 1600 implements a scheduling algorithm for I/O systems not based on static RDMA session priorities but rather handles RDMA sessions' transactions independently based on transaction latency monitoring. Additionally, unlike PFC and DCB based flow management and Differentiated Service Code Point (DSCP) based priorities with allocated bandwidth, the system 1600 performs self-correcting SLO management based on session latency, which may improve achieved throughput/goodput. Session goodput equals the max number of packets received by the receiver in sequence times the packet size per measurement interval.

The controller device 1602 may be embodied as any type of compute device capable of performing the functions described herein. For example, the controller device 1602 may be embodied as, without limitation, a sled 400, a compute sled 800, an accelerator sled 1000, a storage sled 1200, a computer, a server, a distributed computing device, a disaggregated computing device, a network device, a multiprocessor system, a server, a workstation, and/or a consumer electronic device. Similarly, each of the host devices 1604 may be embodied as any type of compute device capable of performing the functions described herein, including, without limitation, a sled 400, a compute sled 800, an accelerator sled 1000, a storage sled 1200, a computer, a server, a distributed computing device, a disaggregated computing device, a network device, a multiprocessor system, a server, a workstation, and/or a consumer electronic device. Illustratively, the controller device 1602 may be embodied as a compute sled 800, and each of the host devices 1604 may be embodied as a storage sled 1200. As described further below, the host devices 1604 are coupled to each other and to the controller device 1602 by a high-speed storage fabric or other high speed network 1606 that supports data storage transfers (e.g., Non-Volatile Memory Express Over Fabrics (NVMe-oF) transfers, RDMA transfers, or other transfers).

As discussed in more detail below, the elements of the system 1600 are configured to transmit and receive data with each other and/or other devices of the system 1600 over the network 1606. The network 1606 may be embodied as any number of various wired and/or wireless networks. For example, the network 1606 may be embodied as, or otherwise include a wired or wireless local area network (LAN), and/or a wired or wireless wide area network (WAN). As such, the network 1606 may include any number of additional devices, such as additional computers, routers, and switches, to facilitate communications among the devices of the system 1600. As shown, the network 1606 illustratively includes a network switch 1608, which may be embodied as a top-of-rack (ToR) switch, a middle-of-rack (MoR) switch, an end-of-row switch, a pod switch, a spine switch, or other network device. Of course, the network 1606 may include multiple additional switches, routers, gateways, or other network devices.

In some embodiments, each of the controller device 1602 and/or the host devices 1604 may be embodied as a virtualized system (e.g., one or more functions executed in virtualized environment(s), such as virtual machine(s) or container(s), in which the underlying hardware resources appear as physical hardware to software executing in the virtualized environment(s), but are separated from the software by an abstraction layer) or a disaggregated system (e.g., composed from one or more underlying hardware devices). In some embodiments, certain functions of the controller device 1602 and/or the host devices 1604 may be duplicated and/or incorporated in other devices. For example, in some embodiments, certain functions of the controller device 1602 may be performed by the one or more host devices 1604 and/or network switches 1608.

Still referring to FIG. 16, in an illustrative embodiment, the controller device 1602 establishes an environment 1620 during operation. The illustrative environment 1620 includes an RDMA session controller 1622, a software defined networking (SDN) controller 1624, and a fabric controller 1626. The various components of the environment 1620 may be embodied as hardware, firmware, software, or a combination thereof. As such, in some embodiments, one or more of the components of the environment 1620 may be embodied as circuitry or collection of electrical devices (e.g., RDMA session controller circuitry 1622, SDN controller circuitry 1624, and/or fabric controller circuitry 1626). It should be appreciated that, in such embodiments, one or more of the RDMA session controller circuitry 1622, the SDN controller circuitry 1624, and/or the fabric controller circuitry 1626 may form a portion of the processor 820, the I/O subsystem 622, the HFI 832, and/or other components of the controller device 1602. Additionally, in some embodiments, one or more of the illustrative components may form a portion of another component and/or one or more of the illustrative components may be independent of one another.

The RDMA session controller 1622 is configured to determine a service level objective (SLO) for an RDMA session. The RDMA session is established between two host devices 1604, and includes multiple RDMA requests. The SLO may be indicative of a guaranteed maximum latency for a percentage of the RDMA requests of the RDMA session.

The SDN controller 1624 is configured to request assignment of queue resources to one or more RDMA requests by an ingress forwarding engine of a network switch 1608. The queue resources may include switch buffers of the network switch 1608. Those functions may be performed by one or more sub-components of the SDN controller 1624, such as a switch telemetry service. As discussed further below in connection with FIG. 20, the switch 1608 may include a queue resource manager to allocate the queue resources to the queue in response to the request to assign of the queue resources, reclaim the queue resources in response to the RDMA request being scheduled, and return the queue resources to a free pool.

The fabric controller 1626 is configured to receive latency data from the host devices 1604. The latency data is indicative of latency of an RDMA request of an RDMA session. In some embodiments, the latency data may be provided to the switch 1608 and/or the host devices 1604 for scheduling RDMA requests.

Still referring to FIG. 16, in an illustrative embodiment, each host device 1604 establishes an environment 1640 during operation. The illustrative environment 1640 includes an RDMA session endpoint 1642, a request scheduler 1644, and a latency monitor 1646. The various components of the environment 1640 may be embodied as hardware, firmware, software, or a combination thereof. As such, in some embodiments, one or more of the components of the environment 1640 may be embodied as circuitry or collection of electrical devices (e.g., RDMA session endpoint circuitry 1642, request scheduler circuitry 1644, and/or latency monitor circuitry 1646). It should be appreciated that, in such embodiments, one or more of the RDMA session endpoint circuitry 1642, the request scheduler circuitry 1644, and/or the latency monitor circuitry 1646 may form a portion of the processor 820, the I/O subsystem 622, the HFI 832, and/or other components of the host device 1604. Further, as shown, each host device 1604 may include one or more I/O devices 1648. The I/O device 1648 may be embodied as any storage device (e.g., NVMe-oF device or other data storage 1250), accelerator device (e.g., FPGA, GPU, ASIC, or other accelerator circuit 1020), or other I/O device accessible through RDMA requests. Additionally, in some embodiments, one or more of the illustrative components may form a portion of another component and/or one or more of the illustrative components may be independent of one another.

The RDMA session endpoint 1642 is configured to send and/or receive RDMA requests with another host device 1604 in an RDMA session. For example, the RDMA session endpoint 1642 may be an application that accesses an I/O device 1648 of a remote host device 1604 via an RDMA session. As another example, the RDMA session endpoint 1642 may be a server that provides I/O device 1648 services to a remote host device 1604 via an RDMA session.

The latency monitor 1646 is configured to determine latency data indicative of latency of an RDMA request of the RDMA session. The latency data may be read from or otherwise based on one or more counters indicative of RDMA session traffic. The counters may be provided by or otherwise included in the HFI 832 or other a network interface controller of the host device 1604.

The request scheduler 1644 is configured to determine a priority associated with the RDMA request as a function of the SLO and the latency data associated with the RDMA request. Determining the priority may include determining whether a time to complete the RDMA request exceeds a time interval associated with the SLO. The priority may be further determined as a function of a latency of an I/O device 1648 associated with the RDMA request. The request scheduler 1644 is further configured to schedule the RDMA request based on the priority. Scheduling the RDMA request based on the priority may include selecting a queue of a network switch 1608 based on the priority and submitting the RDMA request to that queue. It should be understood that some embodiments scheduling the RDMA request may performed by other devices such as the controller device 1602 and/or the network switch 1608 in addition to or alternatively to the host device 1604.

Referring now to FIG. 17, in an illustrative embodiment, the switch 1608 establishes an environment 1700 during operation. The illustrative environment 1700 includes a queue resource manager 1702, multiple ingress forwarding engines 1712, a fabric controller 1716, and switch telemetry services 1718. The various components of the environment 1700 of the switch 1608 may be embodied as hardware, firmware, software, or a combination thereof. Further, in some embodiments, the various components of the environment 1700 may be included in or otherwise provided by other components of the system 1600. For example, in some embodiments, the fabric controller 1716 may be embodied as or otherwise coupled to the fabric controller 1626 of the controller device 1602, and/or the switch telemetry services 1718 may be included in the SDN controller 1624 of the controller device 1602. Additionally, in some embodiments, one or more of the illustrative components may form a portion of another component and/or one or more of the illustrative components may be independent of one another.

As shown, each ingress forwarding engine 1712 includes multiple queues 1714. The queues 1714 (including, e.g., switch buffers) may have different sizes and types based on scheduling flexibility. The switch telemetry services 1718 (e.g., in the SDN controller 1624) will determine the traffic flow (and request through the ingress forwarding engines 1712 to assign additional resources. The resource allocation is centrally managed within the switch system. The queue resource manager 1702 treats the various queues 1714 as free resources that can be assigned/allocated or reclaimed/reallocated based on traffic demands. As shown, the queue resource manager 1702 includes one or more resource manager policies 1704 that are set by the fabric controller 1716. The queue resource manager 1702 may transition through multiple states, including resource allocation 1706, reclaim 1708, and a free pool 1710.

Referring now to FIG. 18, in use, the host device 1604 may execute a method 1800 for monitoring RDMA latency. It should be appreciated that, in some embodiments, the operations of the method 1800 may be performed by one or more components of the environment 1640 of the host device 1604 as shown in FIG. 16. The method 1800 begins in block 1802, in which the host device 1604 monitors latency for an RDMA session. In some embodiments, in block 1804 the host device 1604 may read one or more NIC performance counters from the HFI 832 or other network interface controller. The performance counters may indicate traffic volume or other data indicative of latency for completing RDMA requests with the HFI 832. In block 1806, the host device 1604 may calculate RDMA session latency using the performance counter data. The host device 1604 may calculate the RDMA session latency using Equation 1, below. In Equation 1, RDMARXSND and RDMATXSND are the counts of RDMA Send messages received and sent, respectively. RDMARXWRS and RDMARXRDS are the counts of RDMA Writes received and RDMA Reads received, respectively. RDMATXWRS and RDMATXRDS are the counts of RDMA Writes sent and RDMA Reads sent, respectively. In some embodiments, in block 1808 the host device 1604 may calculate UDP per port latency. The host device 1604 may calculate the UPD per port latency using Equation 2, below. In Equation 2, UDPRXPKTS and UDPTXPKTS are the counts of UDP packets received and sent by a port, respectively.

$\begin{matrix} {{{RDMA}\mspace{14mu}{Session}\mspace{14mu}{Latency}} = {\left\lbrack {\left( {{RDMARXSND} + {RDMATXSND}} \right) - \left( {{RDMARXWRS} + {RDMARXRDS}} \right) + \left( {{RDMATXWRS} + {RDMATXRDS}} \right)} \right\rbrack \times {packetrate}}} & (1) \\ {{{Per}\mspace{14mu}{UDP}\mspace{14mu}{Port}\mspace{14mu}{Latency}} = {\left( {{UDPRXPKTS} + {UDPTXPKTS}} \right) \times {packetrate}}} & (2) \end{matrix}$

In block 1810, the host device 1604 provides latency data to a request scheduler. The host device 1604 may provide RDMA session latency and/or per UDP port latency as described above. In some embodiments, the host device 1604 may provide performance counter data to the request scheduler, which may perform its own latency calculation. In some embodiments, the latency data may be provided to a request scheduler 1644 of the host device 1604 and/or a remote host device 1604, for example to schedule requests to an I/O device 1648 of that host device 1604. In some embodiments, the latency data may be provided to the fabric controller 1626 or other component of the controller device 1602. In some embodiments, the latency data may be provided to the switch 1608. After providing the latency data, the method 1800 loops back to block 1802 to continue monitoring the RDMA session latency.

Referring now to FIG. 19, in use, the host device 1604 may execute a method 1900 for priority scheduling RDMA requests. It should be appreciated that, in some embodiments, the operations of the method 1900 may be performed by one or more components of the environment 1640 of the host device 1604 as shown in FIG. 16. The method 1900 begins in block 1902, in which the host device 1604 receives a service level objective (SLO) for one or more RDMA sessions. The SLOs may be received, for example, from the controller device 1602. Each SLO defines a particular quality of service to be achieved for an RDMA session. The SLO may be defined in terms of a maximum RDMA session latency guaranteed for a particular percentage of RDMA requests. Example SLOs are shown below in Table 1.

TABLE 1 Example SLOs. SLO 1 (Gold) 90% of requests < 100 μs SLO 2 (Silver) 75% of requests < 150 μs SLO 3 (Bronze) 50% of requests < 200 μs

In block 1904, the host device 1604 receives latency data for the RDMA sessions. The host device 1604 may, for example, receive latency data determined as described above in connection with FIG. 18. In some embodiments, the host device 1604 may collect or receive counter data indicative of latency data.

In block 1906, the host device 1604 determines a priority for a RDMA request based on the session SLO and latency. The request priority is assigned based on a time left to completion of the RDMA transaction not exceeding a defined RDMA session latency based on the SLO. For example, request priority may be determined using Equation 3, below. In Equation 3, a lower calculated value has higher priority. The size factor is calculated based on request and response size difference. The I/O device processing latency may depend on the particular I/O device 1648 associated with the RDMA request, such as a storage device, accelerator device, or other device.

$\begin{matrix} {{Priority} = {{SLO} - \left\{ {{{latency}({RDMA\_ request})} + \left. \quad{\left\lbrack {{size\_ factor} \times {{latency}({RDMA\_ request})}} \right\rbrack + {{IO\_ device}{\_ processing}}} \right\}} \right.}} & (3) \end{matrix}$

In block 1908, the host device 1604 schedules the RDMA request based on the RDMA request priority. The host device 1604 may modify the session's transaction handling based on the priority determined with latency monitoring. For example, the host device 1604 may manage allocation and assignment of port buffers of the HFI 832 to manage RDMA traffic according to priority. As another example, the host device 1604 may submit RDMA requests in priority order to the I/O device 1648. After scheduling the RDMA request, the method 1900 loops back to block 1902 to continue scheduling RDMA requests.

Referring now to FIG. 20, in use, the switch 1608 may execute a method 2000 for managing switch queue resources. It should be appreciated that, in some embodiments, the operations of the method 2000 may be performed by one or more components of the environment 1700 of the switch 1608 as shown in FIGS. 16-17. The method 2000 begins in block 2002, in which the switch 1608 receives a queue resource management policy 1704 from the fabric controller (e.g., the controller device 1602). The policy 1704 may include or be based on the RDMA latency data received from the HFI 832 of the host devices 1604.

In block 2004, the switch 1608 requests a queue for an RDMA session. For example, an ingress forwarding engine 1712 may request a queue 1714 in response to a request to assign additional resources received from the switch telemetry service (e.g., the controller device 1602).

In block 2006, the switch 1608 selects a queue for scheduling based on RDMA session priority. Priority may be determined as described above in connection with FIG. 19. In block 2008, the switch 1608 assigns the selected queue to an RDMA session. In block 2010, the switch 1608 schedules the RDMA session using the assigned queue. For example, the switch 1608 may assign RDMA requests received by the ingress forwarding engine to a selected virtual queue. RDMA requests may be output from that virtual queue by an output port of the switch 1608. The RDMA requests may be output based on scheduling priority of the associated queue.

In block 2012, the switch 1608 reclaims the queue and returns the queue to a free pool. The queue resource (e.g., switch buffer) may be reclaimed after the RDMA request has been output by the output port. After being returned to the free pool, the queue resource may be reassigned to an RDMA request. After reclaiming the queue resources, the method 2000 loops back to block 2004 to continue assigning queues to RDMA sessions.

Although illustrated in FIGS. 18-19 as being performed by the host device 1604, it should be understood that in some embodiments the methods 1800, 1900 may be performed by a different compute device, network device, or combination of devices of system 1600. Similarly, although illustrated in FIG. 20 as being performed by the switch 1608, it should be understood that in some embodiments the method 2000 may be performed by a different compute device, network device, or combination of devices of system 1600.

EXAMPLES

Illustrative examples of the technologies disclosed herein are provided below. An embodiment of the technologies may include any one or more, and any combination of, the examples described below.

Example 1 includes a compute device for network quality of service management, the compute device comprising a remote direct memory access (RDMA) session controller to determine a service level objective for an RDMA session, wherein the RDMA session includes a plurality of RDMA requests, and wherein the service level objective is indicative of a guaranteed maximum latency for a percentage of the RDMA requests of the RDMA session; a fabric controller to receive latency data from a host device, wherein the latency data is indicative of latency of an RDMA request of the RDMA session; and a request scheduler to (i) determine a priority associated with the RDMA request as a function of the service level objective and the latency data, and (ii) schedule the RDMA request based on the priority.

Example 2 includes the subject matter of Example 1, and wherein session goodput comprises a maximum number of packets received times a packet size per measurement interval.

Example 3 includes the subject matter of any of Examples 1 and 2, and wherein the latency data is based on one or more counters indicative of RDMA session traffic included in a network interface controller of the host device.

Example 4 includes the subject matter of any of Examples 1-3, and wherein the host device comprises a compute sled, a storage sled, or an accelerator sled.

Example 5 includes the subject matter of any of Examples 1-4, and wherein to determine the priority comprises to determine whether a time to complete the RDMA request exceeds a time interval associated with the service level objective.

Example 6 includes the subject matter of any of Examples 1-5, and wherein to determine the priority further comprises to determine the priority as a function of a latency of an I/O device associated with the RDMA request.

Example 7 includes the subject matter of any of Examples 1-6, and wherein the I/O device comprises a NVMe storage device.

Example 8 includes the subject matter of any of Examples 1-7, and wherein the I/O device comprises an accelerator device.

Example 9 includes the subject matter of any of Examples 1-8, and wherein to schedule the RDMA request based on the priority comprises to select a queue of a network switch based on the priority; and submit the RDMA request to the queue in response to selection of the queue.

Example 10 includes the subject matter of any of Examples 1-9, and further including a switch telemetry service to request assignment of queue resources by an ingress forwarding engine of the network switch to the RDMA request; wherein to select the queue comprises to select the queue in response to a request of the assignment of queue resources.

Example 11 includes the subject matter of any of Examples 1-10, and wherein the network switch comprises a queue resource manager to allocate the queue resources to the queue in response to the request of assignment of the queue resources; reclaim the queue resources in response to scheduling of the RDMA request; and return the queue resources to a free pool in response to reclamation of the queue resources.

Example 12 includes the subject matter of any of Examples 1-11, and wherein the queue resources comprises a switch buffer of the network switch.

Example 13 includes a method for network quality of service management, the method comprising determining, by a compute device, a service level objective for a remote direct memory access (RDMA) session, wherein the RDMA session includes a plurality of RDMA requests, and wherein the service level objective is indicative of a guaranteed maximum latency for a percentage of the RDMA requests of the RDMA session; receiving, by the compute device, latency data from a host device, wherein the latency data is indicative of latency of an RDMA request of the RDMA session; determining, by the compute device, a priority associated with the RDMA request as a function of the service level objective and the latency data; and scheduling, by the compute device, the RDMA request based on the priority.

Example 14 includes the subject matter of Example 13, and wherein session goodput comprises a maximum number of packets received times a packet size per measurement interval.

Example 15 includes the subject matter of any of Examples 13 and 14, and wherein the latency data is based on one or more counters indicative of RDMA session traffic included in a network interface controller of the host device.

Example 16 includes the subject matter of any of Examples 13-15, and wherein the host device comprises a compute sled, a storage sled, or an accelerator sled.

Example 17 includes the subject matter of any of Examples 13-16, and wherein determining the priority comprises determining whether a time to complete the RDMA request exceeds a time interval associated with the service level objective.

Example 18 includes the subject matter of any of Examples 13-17, and wherein determining the priority further comprises determining the priority as a function of a latency of an I/O device associated with the RDMA request.

Example 19 includes the subject matter of any of Examples 13-18, and wherein the I/O device comprises a NVMe storage device.

Example 20 includes the subject matter of any of Examples 13-19, and wherein the I/O device comprises an accelerator device.

Example 21 includes the subject matter of any of Examples 13-20, and wherein scheduling the RDMA request based on the priority comprises selecting a queue of a network switch based on the priority; and submitting the RDMA request to the queue in response to selecting the queue.

Example 22 includes the subject matter of any of Examples 13-21, and further including requesting, by the compute device, assignment of queue resources by an ingress forwarding engine of the network switch to the RDMA request; wherein selecting the queue comprises selecting the queue in response to requesting the assignment of queue resources.

Example 23 includes the subject matter of any of Examples 13-22, and further including allocating, by the network switch, the queue resources to the queue in response to requesting assignment of the queue resources; reclaiming, by the network switch, the queue resources in response to scheduling the RDMA request; and returning, by the network switch, the queue resources to a free pool in response to reclaiming the queue resources.

Example 24 includes the subject matter of any of Examples 13-23, and wherein the queue resources comprises a switch buffer of the network switch.

Example 25 includes a computing device comprising a processor; and a memory having stored therein a plurality of instructions that when executed by the processor cause the computing device to perform the method of any of Examples 13-24.

Example 26 includes one or more non-transitory, computer readable storage media comprising a plurality of instructions stored thereon that in response to being executed result in a computing device performing the method of any of Examples 13-24.

Example 27 includes a computing device comprising means for performing the method of any of Examples 13-24. 

The invention claimed is:
 1. A compute device comprising: circuitry to: receive a service level objective for a remote direct memory access (RDMA) session established with a second compute device, the service level objective to indicate a latency requirement for at least a portion of RDMA requests included in the RDMA session; monitor RDMA requests in the RDMA session to determine a latency of an RDMA request included in the RDMA session; and prioritize the RDMA request for submittal to an input/output (I/O) device hosted by the compute device based on the service level objective and the determined latency of the RDMA request.
 2. The compute device of claim 1, wherein to monitor RDMA requests in the RDMA session comprises the circuitry to monitor one or more counters indicative of RDMA session traffic, the one or more counters included in a network interface controller of the compute device.
 3. The compute device of claim 1, wherein the I/O device hosted by the compute device comprises, a storage device, or an accelerator device.
 4. The compute device of claim 1, wherein to prioritize the RDMA request for submittal to the I/O device comprises to prioritize the RDMA request compared to other requests to the I/O device based on whether a time to complete the RDMA request exceeds a time interval associated with the service level objective.
 5. The compute device of claim 1, wherein to prioritize the RDMA request for submittal to the I/O device comprises to prioritize the RDMA request compared to other requests to the I/O device based on a latency of the I/O device to which the RDMA request is submitted.
 6. The compute device of claim 5, wherein the I/O device hosted by the compute device comprises a Non-Volatile Memory Express (NVMe) storage device or an accelerator device.
 7. The compute device of claim 1, wherein the latency requirement for at least a portion of RDMA requests included in the RDMA session comprises a guaranteed maximum latency for the at least a portion of RDMA requests included in the RDMA session.
 8. A method comprising: receiving, by circuitry of a compute device, a service level objective for a remote direct memory access (RDMA) session, the service level objective to indicate a latency requirement for at least a portion of RDMA requests included in the RDMA session; monitoring RDMA requests in the RDMA session to determine a latency of an RDMA request included in the RDMA session; and prioritizing the RDMA request for submittal to an input/output (I/O) device hosted by the compute device based on the service level objective and the determined latency of the RDMA request.
 9. The method of claim 8, wherein monitoring the RDMA requests in the RDMA session comprises monitoring one or more counters indicative of RDMA session traffic, the one or more counters included in a network interface controller of the compute device.
 10. The method of claim 8, wherein prioritizing the RDMA request for submittal to the I/O device comprises prioritizing the RDMA request compared to other requests to the I/O device based on whether a time to complete the RDMA request exceeds a time interval associated with the service level objective.
 11. The method of claim 8, wherein prioritizing the RDMA request for submittal to the I/O device comprises prioritizing the RDMA request compared to other requests to the I/O device based on a latency of the I/O device to which the RDMA request is submitted.
 12. The method of claim 11, wherein the I/O device hosted by the compute device comprises a Non-Volatile Memory Express (NVMe) storage device or an accelerator device.
 13. The method of claim 12, wherein the latency requirement for at least a portion of RDMA requests included in the RDMA session comprises a guaranteed maximum latency for the at least a portion of RDMA requests included in the RDMA session.
 14. One or more non-transitory computer-readable storage media comprising a plurality of instructions stored thereon that, in response to being executed, cause a compute device to: receive a service level objective for a remote direct memory access (RDMA) session established with a second compute device, the service level objective to indicate a latency requirement for at least a portion of RDMA requests included in the RDMA session; monitor RDMA requests in the RDMA session to determine a latency of an RDMA request included in the RDMA session; and prioritize the RDMA request for submittal to an input/output (I/O) device hosted by the compute device based on the service level objective and the determined latency of the RDMA request.
 15. The one or more non-transitory computer-readable storage media of claim 14, wherein to monitor RDMA requests in the RDMA session comprises to monitor one or more counters indicative of RDMA session traffic, the one or more counters included in a network interface controller of the compute device.
 16. The one or more non-transitory computer-readable storage media of claim 14, wherein to prioritize the RDMA request for submittal to the I/O device comprises to prioritize the RDMA request compared to other requests to the I/O device based on whether a time to complete the RDMA request exceeds a time interval associated with the service level objective.
 17. The one or more non-transitory computer-readable storage media of claim 14, wherein to prioritize the RDMA request for submittal to the I/O device comprises to prioritize the RDMA request compared to other requests to the I/O device based on a latency of the I/O device to which the RDMA request is submitted.
 18. The one or more non-transitory computer-readable storage media of claim 17, wherein the I/O device hosted by the compute device comprises a storage device or an accelerator device.
 19. The one or more non-transitory computer-readable storage media of claim 18, wherein the latency requirement for at least a portion of RDMA requests included in the RDMA session comprises a guaranteed maximum latency for the at least a portion of RDMA requests included in the RDMA session. 